Effect of off-pump coronary artery bypass grafting on risk-adjusted and cumulative sum failure outcomes after coronary artery surgery

BACKGROUND AND AIM: We have shown that cumulative sum (CUSUM) failure analysis may be more sensitive than standard statistical methods in detecting a cluster of adverse patient outcomes after cardiac surgical procedures. We therefore applied CUSUM, as well as standard statistical techniques, to analyze a surgeon's experience with off-pump coronary artery bypass grafting (OPCAB) and on-pump procedures to determine whether the two techniques have similar or different outcomes. METHODS: In 320 patients undergoing nonemergent, first time coronary artery bypass grafting, preoperative patient characteristics, rates of mortality and major complications, and ICU and hospital lengths of stay were compared between the on-pump and OPCAB cohorts using Fisher's exact tests and Wilcoxon two sample tests. Predicted mortality and length of stay were determined using previously validated models of the Cardiac Care Network of Ontario. Observed versus expected ratios of both variables were calculated for the two types of procedures. Furthermore, CUSUM curves were constructed for the on-pump and OPCAB cohorts. A multivariable analysis of the predictors of hospital length of stay was also performed to determine whether the type of coronary artery bypass procedure had an independent impact on this variable. RESULTS: The predicted mortality risk and predicted hospital length of stay were almost identical in the 208 on-pump patients (2.2 +/- 3.9%; 8.2 +/- 2.5 days) and the 112 OPCAB patients (2.0 +/- 2.2%; 7.8 +/- 2.1 days). The incidence of hospital mortality and postoperative stroke were 2.9% and 2.4% in on-pump patients versus zero in OPCAB patients (p = 0.09 and 0.17, respectively). Mechanical ventilation for greater than 48 hours was significantly less common in OPCAB (1.8%) than in on-pump patients (7.7%, p = 0.04). The rate of 10 major complications was 14.9% in on-pump versus 8.0% in OPCAB patients (p = 0.08). OPCAB patients experienced a hospital length of stay that was a median of 1.0 day shorter than on-pump patients (p = 0.01). The observed versus expected ratio for length of stay was 0.78 in OPCAB patients versus 0.95 in on-pump patients. On CUSUM analysis, the failure curve in OPCAB patients was negative and was flatter than that of on-pump patients throughout the duration of the study. Furthermore, OPCAB was an independent predictor of a reduced hospital length of stay on multivariable analysis. CONCLUSIONS: OPCAB was associated with better outcomes than on-pump coronary artery bypass despite a similar predicted risk. This robust finding was documented on sensitive CUSUM analysis, using standard statistical techniques and on a multivariable analysis of the independent predictors of hospital length of stay.     

Coronary artery bypass grafting with and without cardiopulmonary bypass: a comparison analysis

Coronary artery bypass grafting (CABG) using stabilization devices in place of the heart-lung machine is being performed on a wide range of patients. This study retrospectively compared the performance of off-pump coronary artery grafting bypass (OPCAB) with conventional bypass patients over the same 6-month period at The Medical University of South Carolina. Data were collected and compared from the National Cardiac Database of the Society of Thoracic Surgeons (STS). Parameters studied included age, gender, left ventricular ejection fraction (LVEF), previous myocardial infarction (MI), disease severity, number of grafts, complications, blood usage, ventilation times, operating room (OR) time, and hospital length of stay (LOS). There were no significant difference between the patient groups with regard to age, gender, LVEF, previous MI, predicted mortality, and LOS. Operative mortality was also similar in the two groups: conventional bypass 4/117 (3%) and OPCAB 2/86 (2%). The conventional bypass patients (CPB) had significantly (p < 0.05) more diseased vessels (2.9 vs. 2.6) and distal grafts (4.1 vs. 2.7), as compared to the OPCAB group. OPCAB procedures resulted in significantly (p < 0.05) lower mean OR time (365 min vs. 406 min) and reduced mean postoperative ventilation hours (3.4 vs. 8.3 hours), as compared to conventional bypass. There were significantly (p < 0.05) fewer blood transfusions in the OPCAB group (1.1 units vs. 2.4 units), and the percentage of patients transfused blood was significantly less (34.9% vs. 57.3%). Nine out of 95 (9.5%) of patients who presented for OPCAB were converted to conventional bypass. Although there may be potential benefits to OPCAB, further studies must be directed at determining those patients who would benefit most from CABG using the off-pump technique.     

Cumulative sum failure analysis of a policy change from on-pump to off-pump coronary artery bypass grafting

BACKGROUND: Use of the sequential probability cumulative sum (CUSUM) technique may be more sensitive than standard statistical analyses in detecting a cluster of surgical failures. We applied CUSUM methods to evaluate the learning curve after a policy change by a single surgeon from routine on-pump (cardiopulmonary bypass [CPB]) to off-pump coronary artery bypass grafting (OPCAB). METHODS: Fifty-five consecutive first-time coronary artery bypass patients (CPB group) were compared with the next 55 patients undergoing an attempt at routine OPCAB using the same coronary stabilizer. The goal in OPCAB patients was to obtain complete revascularization, albeit with a low threshold for conversion to CPB to maximize patient safety during the learning curve. Preoperative patient risk was calculated using previously validated models of the Cardiac Care Network of Ontario. The occurrence of operative mortality and nine predefined major complications (myocardial infarction, bleeding, stroke, renal failure, balloon pump use, mediastinitis, respiratory failure, life-threatening arrhythmia, and sepsis) was compared between the CPB and OPCAB groups using Wilcoxon, Fisher exact, and two-tailed t tests, as well as CUSUM methodology. An intention to treat analysis was performed. RESULTS: The CPB and OPCAB groups had similar predicted mortality and length of stays (2.2% +/- 2.5%, 8.1 +/- 2.5 days versus 2.4% +/- 3.5%, 8.1 +/- 2.4 days, respectively). The mean number of grafts per patient was 3.1 +/- 0.7 in the CPB group versus 3.0 +/- 0.7 in the OPCAB group (p = 0.45). Two of 55 (3.6%) CPB patients died, as opposed to 1 of 55 (1.8%) OPCAB patients (p = 0.99). Eight of 55 CPB patients (14.5%) incurred major complications, as opposed to 4 of 55 (7.3%) OPCAB patients (p = 0.36). Median hospital length of stay was 6.0 days in the CPB group versus 5.0 days in the OPCAB group (p = 0.28). On CUSUM analysis, the failure curve in CPB patients approached the upper 80% alert line after eight cases, whereas the curve in OPCAB patients reached below the lower 80% (reassurance) boundary 28 cases after the policy change, indicating superior results in the OPCAB group despite the learning curve. CONCLUSIONS: A policy change from coronary artery bypass on CPB to routinely attempting OPCAB can be accomplished safely despite the learning curve. CUSUM analysis was more sensitive than standard statistical methods in detecting a cluster of surgical failures and successes.     

Off-pump myocardial revascularization is associated with less incidence of stroke in elderly patients

Several recent studies have highlighted the potential benefits of using off-pump coronary artery bypass (OPCAB) surgery, particularly in high-risk patients. The aim of this meta-analysis is to assess the effect of OPCAB on the incidence of stroke compared with coronary artery bypass grafting using cardiopulmonary bypass (CPB) in elderly patients. We performed a meta-analysis of all observational studies, published in MEDLINE between 1999 and 2002 and a comparison between the OPCAB and CPB techniques in elderly patients was performed with the outcome of interest being the incidence of stroke. Elderly patients were defined as those aged 70 years or older. Nine studies are included in the meta-analysis. The total number of subjects included was 4,475 patients, of which, 1,253 underwent OPCAB (28%) and 3,222 (72%) underwent CPB. The meta-analysis showed that the OPCAB technique was associated with significantly lower incidence of stroke in elderly patients compared with the CPB technique (1% vs 3%), with an odds ratio of 0.38% to 95% (CI, 0.22 to 0.65). We did not identify any significant heterogeneity and funnel plot asymmetry between the studies included in the meta-analysis. Meta-regression analysis including variables predicting stroke, mortality, and study characteristics did not show any associations affecting the calculated odds ratio of stroke. Despite the fact that this is a meta-analysis of observational studies and adjustment for differences in baseline risk factors between OPCAB and CPB patients was not possible, we believe that this study suggests that the OPCAB technique might be associated with reduced incidence of stroke in the elderly patients undergoing coronary artery bypass grafting.     

The clinical outcome of off-pump coronary artery bypass surgery in the elderly patients

Objective: There has been a body of evidence showing that off-pump coronary artery bypass (OPCAB) may reduce morbidity and mortality in the elderly patients. We reviewed our experience, retrospectively, on elderly patients aged 75 years and older who were operated on using the OPCAB technique. We compared their outcome to a similar group of elderly patients who were operated on using conventional coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) during the same period of time. Methods: Registry data and patients' notes and charts were reviewed for 56 consecutive elderly OPCAB patients (age 78.5±3.5 years) and 87 consecutive CPB patients (age 77.2±2.4 years, P=0.01). Both groups had similar risk factor profiles: Parsonnet score 17.4±4.4 (OPCAB) versus 16.6±5.2 (CPB), P=0.19. We studied in detail their preoperative and postoperative data in order to compare the outcomes of both techniques. Results: The length of stay in the intensive therapy unit (ITU) was 35.4±52.9 h for OPCAB patients and 77.6±144.9 h for CPB patients (P=0.0008). No patient died within 30 days in the OPCAB group, whilst ten (11%) CPB patients (P=0.0066) died within 30 days. The incidence of serious complications (including pulmonary oedema, septicaemia, permanent stroke and renal dysfunction requiring haemofiltration or haemodialysis) was one (2%) in the OPCAB group and 11 (13%) in the CPB group (P=0.028). CPB patients required a significantly higher number ten (12%) of intra-aortic balloon pumps (IABP) inserted compared to only one patient (2%) in the OPCAB group who required IABP insertion (P=0.05). Nine (11%) CPB patients were re-operated on for bleeding compared to no OPCAB patient (0%) needing re-operation, P=0.011. Conclusions: Although the mean age of the OPCAB group was significantly higher than the CPB group, the OPCAB group showed a significant reduction in postoperative serious morbidity, ITU stay and mortality. We believe that such a conclusion may have some effect on the decision-making and cost-effectiveness when performing coronary bypass surgery on the elderly population.     

Surgical revascularization in patients with poor left ventricular function: on- or off-pump?

BACKGROUND: Patients with left ventricular dysfunction and low ejection fraction (EF) are at high-risk of complication and mortality after coronary artery bypass grafting (CABG). The potential success of off-pump CABG in this high-risk population has yet to be determined. The purpose of this study is to compare the outcome of off-pump coronary artery bypass (OPCAB) and conventional coronary artery bypass (CCAB) in patients with poor left ventricular function, all from a single institution. METHODS: Data on patient demographics, preoperative risk factors, operative and postoperative outcomes were collected retrospectively on all patients having undergone isolated CABG between January 1, 1998, and October 31, 2001. RESULTS: A total of 77 patients (31 OPCAB/46 CCAB) were identified as having an ejection fraction (EF) of < or = 0.35. Of these, 52 had EF < or = 0.30 (21 OPCAB/31 CCAB) and 31 patients had EF < or = 0.25 (10 OPCAB/21 CCAB). Operative mortality was 3.2% after the OPCAB procedure versus 10.9% for the CCAB (p = 0.39). Use of intraaortic balloon pump (6.5%) was rarely required. The OPCAB procedure resulted in significantly less requirement for blood transfusions (p < 0.05), fewer distal anastomoses per patient (p < 0.01), and a higher incidence of atrial fibrillation (p < 0.05) compared with CCAB. CONCLUSIONS: Patients with poor left ventricular function may undergo surgical revascularization using off-pump technique with relatively good results and low mortality levels. The lower number of grafts performed on the off-pump procedure did not seem to affect clinical outcomes.     

Coronary artery bypass in patients 80 years and over: is off-pump the operation of choice?

BACKGROUND: Octogenarians are at increased risk for perioperative morbidity and mortality after coronary artery bypass. In this study we compared our experience with patients undergoing on-pump coronary artery bypass (CAB) and those undergoing off-pump coronary artery bypass (OPCAB) to assess outcomes. METHODS: We used hospital database analysis in patients 80 years and older who underwent nonemergent coronary artery bypass with (N = 169) and without (N = 60) cardiopulmonary bypass from January 1999 through June 2001. RESULTS: Both groups were at increased perioperative risk based on the Society of Thoracic Surgeons risk model (7.7% OPCAB vs 5.8% CAB, p = 0.03). There were no operative deaths in the OPCAB group but there were eight (4.7%) in the CAB group (p = NS). Perioperative stroke (0% OPCAB vs 7.1% CAB, p = 0.04), prolonged ventilation (1.7% OPCAB vs 11.8% CAB, p = 0.02), and transfusion rate (33% OPCAB vs 70.4% CAB, p < 0.001) were all lower in the OPCAB group. A shorter hospital stay (6.3 days OPCAB vs 11.5 days CAB, p < 0.001) resulted in lower hospital cost in the OPCAB group ($9,363 OPCAB vs $12,312 CAB, p < 0.001). CONCLUSIONS: In this study, off-pump coronary artery bypass grafting in elderly patients was associated with fewer complications, a shorter hospital stay, and lower hospital cost. Off-pump coronary artery bypass grafting may be the operation of choice for octogenarians requiring surgical myocardial revascularization.     

Is routine application of off-pump coronary artery bypass grafting warranted?

The limitation and indication of off-pump coronary artery bypass grafting (OPCAB) remain controversial. Since May 1999, we have applied OPCAB for all isolated coronary bypass cases routinely. Intraoperative conversion to CCAB occurred in 8 patients (10.8%). The main reasons for conversion were intramyocardial coronary arteries and arythmia-induced hemodynamic instability in the acute phase of myocardial infarction. We evaluated the results of OPCAB as compared to conventional coronary artery bypass (CCAB) as a historical control. The operative mortality was 1.6% in both groups. Postoperative complications including renal failure and requirements of circulatory support were significantly less in OPCAB. Postoperative max CPK-MB value, the amount of postoperative bleeding and the requirement of transfusion were also significantly less in OPCAB. Only neurological complication in OPCAB was temporary delirium in a high-aged patient, whereas three patients developed neurological complications including permanent stroke in CCAB. Right heart bypass was effectively utilized to maintain hemodynamics and expose the posterior vessels in patients with severely dilated and poorly functioning left ventricle (EF: 24-31%) and a patient with multiple severe stenosis in cerebral arteries. Coronary angiogram performed after the operation demonstrated 94% of graft patency. These results warrant the further application of OPCAB for multivessel surgical revascularization.     

Cost-effectiveness of minimally invasive coronary artery bypass surgery.

BACKGROUND: Coronary artery bypass grafting without cardiopulmonary bypass is gaining popularity as an alternative to conventional on-pump technique for myocardial revascularization. This includes minimally invasive direct coronary artery bypass (MIDCAB) and full sternotomy off-pump (OPCAB) methods. These two approaches should be evaluated for financial and clinical appropriateness. METHODS: Records of patients who had single or double bypass (internal mammary artery and/or saphenous vein) grafts between January 1997 and June 1998 were reviewed. These included 44 MIDCAB, 62 OPCAB, and 243 conventional coronary artery bypass (CCAB) patients. Univariate analysis was applied to pre, intra, and postoperative variables, comparing MIDCAB and OPCAB to the CCAB group. Procedural cost information was obtained from participating institutions. RESULTS: MIDCAB patients compared to CCAB patients had a higher predicted risk (5.4+/-11 versus 2.3+/-2.8, p = 0.012) and OPCAB patients had a predicted risk of 5.3+/-7.8. MIDCAB and OPCAB procedures required less operating room time and blood utilization. Observed operative mortality rates were MIDCAB 4.5%, OPCAB 1.6%, and CCAB 2.8% (not significant). Mean hospital costs were CCAB at $19,000, OPCAB at $15,000, and $17,000 for MIDCAB. CONCLUSIONS: Off pump procedures currently reflect acute episode-of-care cost savings over CCAB.     

Multivessel off-pump coronary artery bypass surgery in the elderly.

OBJECTIVE: Coronary artery bypass grafting in the elderly patient is associated with increased perioperative morbidity and mortality. The avoidance of cardiopulmonary bypass (CPB) in this population is potentially beneficial. We examined our initial experience with off-pump multivessel coronary artery revascularization in patients aged 70 years and older. METHODS: In a consecutive series of 300 off-pump coronary artery bypass (OPCAB) operations performed by a single surgeon between 1996 and 1999, 98 patients were aged 70 years and older. These patients were compared with a consecutive cohort of 497 patients aged 70 years and older operated on with CPB in the same institution from 1995 to 1996, period where OPCAB surgery was not performed in our institution. RESULTS: Patients in the beating heart group were older (75+/-4 vs. 74+/-3 years; P=0.001). Gender distribution and other preoperative risk factors were comparable for the two groups. On average, 3.0+/-0.8 and 2.8+/-0.7 grafts per patient were completed in the OPCAB and the CPB groups, respectively (P=0.007). Perioperative mortality rates (OPCAB group, 3.1%; CPB group, 3.6%), perioperative myocardial infarction (OPCAB, 2.0%; CPB, 5.1%) and neurologic events (OPCAB, 1.0%; CPB, 3.2%) were comparable for the two groups. The incidence of postoperative atrial fibrillation was lower in the OPCAB group (42 vs. 54%; P=0.05). The need for allogenic blood transfusions was significantly less in the OPCAB group (53 vs. 82%; P=0.001). CONCLUSIONS: In patients aged 70 years and older, multivessel OPCAB surgery is associated with lower rates of postoperative atrial fibrillation and reduced transfusion requirements. Multivessel OPCAB in the elderly patient is an acceptable alternative to procedures performed with CPB.     

Off-pump coronary artery bypass grafting surgery in early stage myocardial infarction treatment

We evaluated the surgical results of off-pump coronary artery bypass grafting (OPCAB) performed within the first 12 h of infarction in patients with acute myocardial infarction. From January 2005 to January 2007, emergency coronary artery bypass grafting without cardiopulmonary bypass was performed in 56 patients with acute coronary syndromes. The mean age was 62.9 (range, 51-86) years. All patients underwent OPCAB via sternotomy. An average of 2.5 +/- 1.1 grafts per patient were performed. The mortality rate was 7.1% (4 of 56 patients). One patient suffered from postoperative stroke (1.7%), and 3 (5.3%) needed hemofiltration for acute renal failure. Postsurgery elective coronary angiography (n = 21) showed no significant stenosis. These results indicate that emergency OPCAB can be applied to patients with acute myocardial infarction with low morbidity and mortality and excellent early results.     

Early results of off-pump coronary artery bypass

Objective: The purpose of this study is to compare the operative results of off-pump coronary artery bypass (OPCAB) and on-pump (conventional) coronary artery bypass (CCAB), to clarify qualitative problems and whether OPCAB is less invasive or not. Methods: OPCAB was consecutively performed in 63 patients and CCAB in 63 patients between July 1998 and December 2003. Results: The mean number of bypass grafts was 2.43 ±0.82 in the OPCAB group and 2.70±0.71 in the CCAB group (p=0.096). In-hospital mortality was 0% in the OPCAB group and 3.2% in the CCAB group. The incidence of perioperative myocardial infarction was 0% in the OPCAB group and 3.2% in the CCAB group. The incidence of postoperative major complications was significantly lower in the OPCAB group than in the CCAB group (OPCAB group=4 complications, CCAB group=13 complications). Cerebrovascular accidents occurred in 1.6% of patients in both groups. The incidence of sternal infection or mediastinitis was 0% in the OPCAB group and 3.2% in the CCAB group. The early patency rate of graft was 94.0% in the OPCAB group and 92.8% in the CCAB group, and was not significantly different (p=0.822). Conclusion: Operative mortality and major complications after surgery in OPCAB were lower than that in CCAB. The early patency rate in OPCAB was as good as that in CCAB. It is considered that OPCAB is less invasive and the quality of bypass in OPCAB is as good as that in CCAB.     

Safety and efficacy of off-pump coronary artery bypass grafting

BACKGROUND: We evaluated the application of the off-pump coronary artery bypass (OPCAB) procedure relative to safety and efficiency as measured by operative mortality postoperative complications and longitudinal outcome. METHODS: Three hundred and fifty OPCAB patients were compared to 3,171 on-pump or conventional coronary artery bypass (CCAB) patients between January 1, 1997 and December 31, 1998. The groups were divided into three preoperative predicted risk categories: low-risk (0 to 2.59%), medium-risk (2.6 to 9.9%), and high-risk (> or =10%). Society of Thoracic Surgeons National Cardiac Surgery Database definitions and predicted risk group models were utilized to compare all preoperative, intraoperative, and postoperative variables using univariate analysis. RESULTS: Overall comparison of the immediate outcome of CCAB and OPCAB shows little statistical significance in the variables analyzed. The operative mortality was 3.4% in both groups. When the immediate outcome was compared between groups (CCAB vs OPCAB), as well as individual risk groups (low, medium, and high), similar patterns of operative variables and postoperative complications were observed. The operative mortality in the low-risk group was 1.1% for CCAB and 1.4% for OPCAB; 7% for CCAB and 6% for OPCAB in the medium-risk group; and in the high-risk group 28.5% for CCAB compared to 7.7% for OPCAB group (p = 0.008). Short-term follow-up shows a trend of increased recurring angina and reinterventional procedures in the OPCAB patients. CONCLUSIONS: Safety for OPCAB is assessed through retrospective data review. Longitudinal follow-up for survival, reintervention, and quality of postoperative document efficacy and patency rates, compared to on-pump procedures, is mandatory. This study documented the immediate safety of the OPCAB procedure. Preliminary findings at 1-year follow-up is an important finding in this study, but it is not conclusive at this time. Long-term longitudinal follow-up is required to assess the future effectiveness of OPCAB.     

Stroke after conventional versus minimally invasive coronary artery bypass

BACKGROUND: Postoperative stroke is a serious complication after coronary artery bypass grafting with cardiopulmonary bypass (on-pump), and portends higher morbidity and mortality. It is unknown whether an off-pump cardiopulmonary bypass (OPCAB) approach may yield a lower stroke rate over conventional on-pump coronary artery bypass grafting. METHODS: From June 1994 to December 2000, OPCAB was performed in 2,320 patients and compared with 8,069 patients who had on-pump coronary artery bypass grafting, during the same period of time. The patients undergoing OPCAB were randomly matched to on-pump patients by propensity score. A logistic regression model was used to test the difference in the postoperative stroke rate between OPCAB and on-pump procedures controlling for the correlation between matched sets. A multiple logistic regression model predicting the risk of stroke adjusted by stroke risk factors and operation type was also computed. RESULTS: Matches by propensity score were found for 72% of the patients undergoing OPCAB. Patients undergoing on-pump coronary artery bypass grafting were 1.8 (95% confidence interval 1.0 to 3.1, p = 0.03) times more likely to suffer a stroke postoperatively than OPCAB patients after controlling for preoperative risk factors through matching. Independent predictors of stroke identified from the multiple logistic model included on-pump operation (versus OPCAB operation), female gender, 4 to 6 vessels grafted (versus <4 grafts), hypertension, history of previous cerebrovascular accident, carotid artery disease, chronic obstructive pulmonary disease, and depressed ejection fraction. CONCLUSIONS: Off-pump cardiopulmonary bypass avoids the risks of cardiopulmonary bypass and atrial trauma. A substantially lower stroke rate suggests that OPCAB is a neurologically safe treatment option for revascularization.     

In-hospital outcomes of off-pump versus on-pump coronary artery bypass procedures: a multicenter experience.

BACKGROUND: Concern about the possible adverse effects of the cardiopulmonary bypass (CPB) pump and advances in retractors and operative techniques to access all coronary segments have resulted in increased interest in off-pump coronary artery bypass (OPCAB) procedures. Four of the Northern New England Cardiovascular Disease Study Group centers initiated OPCAB programs in 1998. We compared the preoperative risk profiles and in-hospital outcomes of patients done off-pump with those done by conventional coronary artery bypass (CCAB) with CPB. METHODS: Between 1998 and 2000, 1,741 OPCAB and 6,126 CCAB procedures were performed at these four medical centers. Minimally invasive direct coronary artery bypass grafting procedures were excluded. Data were available for patient and disease risk factors, extent of coronary disease and adverse in-hospital outcomes. RESULTS: The OPCAB and CCAB groups were somewhat different in their preoperative patient and disease characteristics. The OPCAB patients were more likely to be female and to have peripheral vascular disease. The CCAB patients were more likely to have an ejection fraction less than 0.40 and be urgent or emergent at operation. However, overall predicted risk of in-hospital mortality, based on preoperative factors, was similar in the OPCAB and CCAB groups; the mean predicted risk was 2.6% (p = 0.567). Crude rates of mortality (2.54% OPCAB versus 2.57%, CCAB), intraoperative or postoperative stroke (1.33% versus 1.82%), mediastinitis (1.10% versus 1.37%), and return to the operating room for bleeding (3.46% versus 2.93%) did not differ significantly. The OPCAB patients did have a statistically significant reduction in the need for intraoperative or postoperative intraaortic balloon pump support (2.31% versus 3.41%; p = 0.023) and in the incidence of postoperative atrial fibrillation (21.21% versus 26.31%; p < 0.001). Adjustment for preoperative risk factors and extent of coronary disease did not substantially change the crude results. Median postoperative length of stay was significantly shorter (5 days versus 6 days, p < 0.001) for OPCAB patients than for CCAB patients. CONCLUSIONS: This multicenter study showed that patients having OPCAB are not exposed to a greater risk of short-term adverse outcomes. These data also provided evidence that patients having OPCAB have significantly lower need for intraoperative or postoperative intraaortic balloon pump, lower rates of postoperative atrial fibrillation, and a shorter length of stay.     

Is low ejection fraction safe for off-pump coronary bypass operation?

BACKGROUND: Does the manipulation of the heart during off-pump coronary artery bypass (OPCAB) procedure further compromise the hemodynamic stability of a patient with depressed left ventricular function compared with the conventional coronary artery bypass (CCAB) approach? Does this manipulation induce a more dramatic hypoperfused state that may contribute to an increase in the incidence of related complications or mortality? This retrospective review of data attempted to answer the above concern. METHODS: Between January 1, 1998, and June 30, 1999, 177 patients with ejection fractions of 30% or less underwent full sternotomy coronary artery bypass grafting at our institution. Of these patients, 45 underwent OPCAB procedures and 132 patients underwent CCAB. Pre-, intra-, and postoperative variables as identified by The Society of Thoracic Surgeons National Cardiac Surgery Database were compared using univariate and logistical regression analysis. RESULTS: Despite recognized hemodynamic derangement during cardiac displacement, these groups of OPCAB patients appeared to tolerate the procedure well. Univariate analysis of cardiac enzyme leak and blood loss was statistically significant in the OPCAB patients. Utilizing regression analysis, cardiopulmonary bypass was the only predictor for all postoperative complications. CONCLUSIONS: Multivessel coronary artery bypass utilizing the OPCAB approach in patients with depressed left ventricular function of equal to or less than 30% is appropriate and applicable. Analysis of CCAB and OPCAB variables was nonsignificant except for operative and postoperative blood loss and peak cardiac enzyme leak. Attention to intraoperative detail and hemodynamic management could be credited for the success with OPCAB.     

Off-pump multivessel coronary artery surgery in high-risk patients

BACKGROUND: Coronary artery bypass surgery on cardiopulmonary bypass is associated with significant morbidity and mortality, which may be more marked in high-risk patients. We evaluated our results of off-pump coronary artery bypass (OPCAB) in high-risk patients with multivessel coronary artery disease and compared them with results in similar patients who underwent operation on cardiopulmonary bypass. METHODS: A total of 1,075 patients who underwent OPCAB between October 1996 and June 2001 and who had one or more of the following risk factors were included in the study: poor left ventricular function (EF < or = 30%), advanced age (> 70 years), left main stenosis, acute myocardial infarction, and redo coronary artery surgery. These patients were compared with 2,312 similar patients who underwent coronary artery bypass grafting on cardiopulmonary bypass during the same period. Preoperative risk factors, intraoperative variables, and postoperative results were analyzed and compared between two groups. RESULTS: The average number of grafts was 3.0 +/- 0.4 and 3.2 +/- 0.3 in the off-pump (OPCAB) and on-pump (CCAB) groups, respectively. Hospital mortality was 3.2% and 4.5% in OPCAB and CCAB groups respectively (p = 0.109). Perioperative myocardial infarction, requirement of inotropic agents, stroke, and renal dysfunction were comparable in two groups. Intubation time (19 +/- 5 vs 24 +/- 6 hours, p < 0.001), mean blood loss (362 +/- 53 vs 580 +/- 66 mL, p < 0.001), atrial fibrillation (14.3 vs 19.7%, p < 0.001), and prolonged ventilation (4.6 vs 7.6%, p = 0.002) were less in OPCAB group. Intensive care unit stay (20 +/- 8 hours) and hospital stay (6 +/- 3 days) were significantly less in the OPCAB group (p < 0.001). CONCLUSIONS: Off-pump coronary artery surgery can be safely performed in high-risk patients with multivessel coronary artery disease. Operative mortality is comparable to that associated with on-pump surgery, and avoidance of cardiopulmonary bypass is associated with reduced postoperative morbidity in these patients.     

The effect off-pump coronary artery bypass surgery on in-hospital mortality and morbidity.

OBJECTIVE: Off-pump coronary artery bypass (OPCAB) surgery is being increasingly reported to show better outcomes compared to conventional on bypass grafting. We examined the effect of OPCAB on in-hospital mortality and morbidity, while adjusting for patient and disease characteristics, in four institutions in the North West of England. METHODS: Between April 1997 and March 2001, 10,941 consecutive patients underwent isolated coronary artery bypass surgery at these four institutions. Of these, 7.7% were performed off-pump. We used logistic regression to examine the effect of OPCAB on in-hospital mortality and morbidity after adjusting for potentially confounding variables. RESULTS: The crude odds ratio (OR) for death (off-pump versus on-pump coronary bypass grafting) was 0.48 (95% confidence interval, CI 0.26-0.92; P=0.023). After adjustment for all major risk factors, the OR for death was 0.59 (95% CI 0.31-1.12; P=0.105). Off-pump patients had a substantially reduced risk of post-operative stroke (0.6 versus 2.3%, respectively; adjusted OR 0.26 (95% CI 0.09-0.70; P=0.008) and a significant reduction in post-operative hospital stay. Other morbidity outcomes were similar in both groups. CONCLUSIONS: Off-pump coronary artery bypass incurs no increased risk of in-hospital mortality. In contrast, there is a significant reduction in morbidity in patients undergoing off-pump coronary bypass grafting when compared to that performed on cardiopulmonary bypass.     

Off-pump surgery decreases postoperative complications and resource utilization in the elderly.

BACKGROUND: Bypass surgery in the elderly (age >70 years) has increased mortality and morbidity, which may be a consequence of cardiopulmonary bypass. We compare the outcomes of a cohort of elderly off-pump coronary artery bypass (OPCAB) patients with elderly conventional coronary artery bypass grafting (CABG) patients. METHODS: Chart and provincial cardiac care registry data were reviewed for 30 consecutive elderly OPCAB patients (age 74.7 +/- 4.2 years) and 60 consecutive CABG patients (age 74.9 +/- 4.1 years, p = 0.82) with similar risk factor profiles: Parsonnet score 17.2 +/- 8.1 (OPCAB) versus 15.6 +/- 6.5 (CABG), p = 0.31; and Ontario provincial acuity index 4.5 +/- 1.9 (OPCAB) versus 4.3 +/- 2.0 (CABG), p = 0.65. RESULTS: Mean hospital stay was 6.3 +/- 1.8 days for OPCAB patients and 7.7 +/- 3.9 days for CABG patients (p < 0.05). Average intensive care unit stay was 24.0 +/- 10.9 h for OPCAB patients versus 36.6 +/- 33.5 h for CABG patients (p < 0.05). Atrial fibrillation occurred in 10.0% of OPCAB patients and 28.3% of CABG patients (p < 0.05). Low output syndrome was observed in 10% of OPCAB patients and 31.7% of CABG patients (p < 0.05). Cost was reduced by $1,082 (Canadian) per patient in the OPCAB group. Postoperative OPCAB graft analysis showed 100% patency. CONCLUSIONS: OPCAB is safe in the geriatric population and significantly reduces postoperative morbidity and cost.     

Does off-pump coronary artery bypass (OPCAB) surgery improve the outcome in high-risk patients?: a comparative study of 1398 high-risk patients.

OBJECTIVE: Although there has been some evidence supporting the theoretical and practical advantages of off-pump coronary artery bypass (OPCAB) over the conventional coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB), it has not yet been determined which group of patients would benefit most from it. It has been advocated recently that high-risk patients could benefit most from avoidance of CPB. The aim of this retrospective study is to assess the efficacy of the OPCAB technique in multi-vessel myocardial revascularization in a large series of high-risk patients. METHODS: The records of 1398 consecutive high-risk patients who underwent primary isolated CABG at Harefield Hospital between August 1996 and December 2001 were reviewed retrospectively. Patients were considered as high-risk and included in the study if they had a preoperative EuroSCORE of > or =5. Two hundred and eighty-six patients were operated on using the OPCAB technique while 1112 patients were operated on using the conventional CABG technique with CPB. The OPCAB patients were significantly older than the CPB patients (68.1+/-8.3 vs. 63.7+/-9.9 years, respectively, P<0.001). The OPCAB group included significantly more patients with poor left ventricular (LV) function (ejection fraction (EF) < or =30%) (P<0.001) and more patients with renal problems (P<0.001). RESULTS: There was no significant difference in the number of grafts between the groups. The CPB patients received 2.8+/-1.2 grafts per patient while OPCAB patients received 2.8+/-0.5 grafts per patient (P=1). Twenty-one (7.3%) OPCAB patients had one or more major complications, while 158 (14.2%) CPB patients (P=0.008) developed major complications. Thirty-eight (3.4%) CPB patients developed peri-operative myocardial infarction (MI) while only two (0.7%) OPCAB patients developed peri-operative MI (P=0.024). The intensive therapy unit (ITU) stay for OPCAB patients was 29.3+/-15.4 h while for CPB patients it was 63.6+/-167.1 h (P<0.001). There were ten (3.5%) deaths in the OPCAB patients compared to 78 (7%) deaths in the CPB patients (P=0.041) within 30 days postoperatively. CONCLUSIONS: This retrospective study shows that using the OPCAB technique for multi-vessel myocardial revascularization in high-risk patients significantly reduces the incidence of peri-operative MI and other major complications, ITU stay and mortality. Even though the OPCAB group included a significantly higher proportion of older patients with poor LV function (EF < or =30%) and renal problems, the beneficial effect of OPCAB was evident.